This chart shows that sensitivity alone doesn't tell the whole story. A sealed cab relies on the cone alone for output, and when the driver runs out of xmax maximum output goes down. A ported cab shifts the load to the port down low, and at the same time reduces the cone excursion, so it will have higher maximum SPL than sealed. This situation also applies to the S10 and S12 ported versus sealed, or for that matter most ported versus sealed cabs.